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LETTER FROM THE EDITOR | 191

Revelations about a turbulent star

We are talking about stars in this first issue of 2012. About Eta Carinae, a star so rich in mysteries that it is actually two stars, Eta Carinae A and Eta Carinae B. More precisely stated, it is a binary stellar system. It has become the subject of the Pesquisa FAPESP cover story because an international team of astrophysicists, headed by Brazilians, has proposed a consistent explanation for one of the most intriguing questions surrounding it, namely: why is it that every five and a half years the enigmatic star stops shining for about 90 days, when seen by an observer on Earth, if the eclipse of the X-ray emissions caused by the passage of Eta A only lasts for about 30 days?

The answer put forth by the group led by Augusto Damineli and Mairan Teodoro, both of them from the University of São Paulo (USP), is that in addition to the fairly well-known eclipse, a second phenomenon is at play: a collapse or loss of balance in the zone where the winds from the two stars collide, extending the Eta Carinae blackout by two extra months. Consequently, the loss of brightness of the X-ray band is maintained, along with an emission of the ultraviolet spectrum. It is precisely there in this ultraviolet flash, already a great novelty, highlights Marcos Pivetta, our special editor and author of the article that attempts, starting on page 20, to explain the new scientific findings about Eta Carinae more clearly. The teams of astrophysicists reached this and other proposals by analyzing the data from five land-based telescopes in South America, during the most recent blackout of this temperamental star, between January and March of 2009.

From remote areas in the Universe to that which is closest to us, namely, our body, this issue required equal efforts from all the journalists to put extremely complicated scientific results into plain language. I mention this in connection, for example, with the article on the relation between the workings of the thymus and the onset of autoimmune diseases among people with Down’s syndrome. The thymus per se is a gland that is seldom researched and  poorly understood, even by physicians and other health professionals. Few people know that this organ, which lies behind the sternum and in front of the heart – and that in newborns takes up almost the full extension of the chest – is a sort of advanced training field for an important group of defense cells, because it is here that these cells, the T lymphocytes, learn to distinguish between parts of the body and foreign organisms that must be eliminated in order to preserve the body. The problem is that this learning process does not work very well in people with Down’s syndrome. The article by our science editor, Ricardo Zorzetto, and by our collaborator, Francisco Bicudo, explains why.

Unlike what takes place in areas previously covered by science, the challenge in the humanities is less the issue of clarifying relevant findings and discoveries that are obscure to lay people, and more the issue of presenting a scientific basis for what, at first sight, seems like the common identification or discussion of a given aspect of daily social life. Thus, it seems strange that one should apply a scientific methodology to the question of the extent that decisions concerning Brazilian foreign policy have any impact on the country’s internal reality. Or to the discussion about the role of the Legislative branch for Brazilian diplomacy, or if it even has such as role. However, it is precisely the scientific framework that supports the advance of knowledge regarding political science issues that are briefly described in the article by our humanities editor, Carlos Haag, on the relations between Itamaraty (the Brazilian Foreign Office) and Congress.

Enjoy your reading and may all our readers have an excellent year in 2012!

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